Heat conserver for ranges



Nov. 8, 1938,

M. A, CROSSMAN 7 HEAT CONSERVER FOR RANGES Filed Oct. 22, 1957 Patented Nov. 8, 1938 UNITED- STATES PATENT tries;

12 Claims.

The invention herein set forthis concerned with kitchen ranges and the like, and its object is to conserve the heat of the fire, direct the products of combustion and heated gases from the combustion air so as to heat the oven of the range efficiently and quickly, prevent radiation, convection and leakage losses from the top of the range, and to prevent the gases heated in r the combustion chamber of the range from being dilutedby cold air seeping into the combustion chamber through cracks in the front of the range and adjacent parts of the range top. In this description the term kitchen range is intended to include the stoves which are used in kitchens for cooking and maintaining a supply of domestic hot water, and other stoves of analogous character. 'The utility of the invention is most pronounced in connection with ranges designed to burn coal which have been converted to oil burning stoves by the installation of oil burners in the fire'pot, and will be explained in the following specification withreference to that use and its combination with such a range. But I wish to make it clearly understood that the principles of the invention are not limited to that use but include all other uses and combinations in which any part of the new features contained in the invention may be applied.

Great numbers of ranges designed to burn coal or wood as the source of heat have been converted to use oil by the installation of oil burning equipment in the fire pot. All the makes of ranges used in considerable numbers follow very much "the same pattern and are alike in having a deep fire pot extending across the entire width of the range at one end, which is usually referred to as the front, and in having the top made with a large opening within its rim'which is crossed by removable bridge bars so arranged as, when in place, to leave two or more pairs of circular holes which are closed by circular lids. "Such lids and bridge bars fit loosely at best, and frequently become somewhat warped. "I'heypermit leakage of gases from the fire pot into the room, or leakage of outside air into the spaces beneath the range top, depending onthe condition of the fire and placement of the dampers. Inward leakage of air occurs elsewhere as well.

The various oil burners provided for such ranges also follow similar patterns, and practically all of themprovidetwo cylindrical annular-burners located beneath the two holes of the 55 stove 'top which'overlie the fire .pot. The-surrounding conditions require the burners to be set at a height such that the zone of heat generation is in the upper part of the fire pot, and the products of combustion rise rapidly and highly heat the top of the stove, but do not quickly or efiiciently heat the oven or the water chamber which is commonly formed in one of the'bo-unding walls of the fire pot and is connected with the storage tank for providing a supply of hot water. The products of combustion tend to pass directly to the outlet flue of the range, and only in small measure or with diificulty can they be directed by the ordinary dampers of the range to pass around the baking oven and heat it uniformly enough and hot enough for properbaking. My observation and information is to the efiect that with many ranges in which 011 burners are used, it requires both burners to be run for two hours or more to make the oven hot enough for baking those co-mestibles which require a temperature as high as 400 F. and that with some makes of range it is impossible even to attain that temperature in the lower part of the oven.

I have devised an attachment adapted to be inserted into standard ranges without any change in the structure of the range, by which the difficulties above referred to are overcome and the heat generated by the oil burning equipment is so conserved and efliciently used that the oven may be heated in, much less time, the water may be heated hotter and more quickly than heretofore, and all cooking performed with less expenditure of fuel. The attachment may be made in different dimensions to fit different ranges, but its principles are the same in all cases. The invention consists both in the attachment itself, in its various modifications and embodiments, and in the combination of such an attachment with the stove or range in which it is installed. One illustrative embodiment of the attachment is shown in the accompanying drawing in which,--

Fig. 1 is a perspective view of an attachment made of two main parts and a number of auxiliary parts, shown with the main parts disassembled from one another;

Fig. 2 is a plan view of a portion of a. cooking range showing my attachment installed therein;

Fig. 3 is a cross section of the range taken on line 3--3 of Fig. 2, but showing only the upper portion of the fire pot and the adjacentoven;

Figs. 4 and 5 are perspective views of two alternatively used, covers for lids for the holes which r the range top and the front wall 26.

are provided in the heat conserving attachment over the oil burners;

Fig. 6 is a fragmentary sectional View on a larger scale of the lid shown'in Fig. 4;

Fig. '7 is a fragmentary cross section of the upper part of the range taken on line 1-1 of Fig. 2.

Like reference characters designate the same parts wherever they occur in all the figures.

This heat conserving device consists essentially of a plate of heat refractory material which is placed over the fire pot and to a greater or less extent over the flue between the top of the range and the oven, a short distance below the range top. In practice it is made of a number of pieces adjustably connected to one another in a manner to adapt it to different ranges so as to control the flow of hot gases from the. burners and prevent outward leakage of gases and fumes and inward leakage of air through cracks in the top and upper side portions of the range. The embodiment here shown consists of a main plate H], a rear extension plate II, and adjustable flange pieces [2, I3, l4, l5 and I6. All of these pieces may be made of sheet metal, and I prefer sheet iron because of its low cost as compared with other metals and its ability to withstand exposure to intense heat and severe temperature changes without substantial deterioration over long periods of time. While other refractory materials than metals may be used, the metals are preferred to non-metals because of their toughness and the fact that plates sufliciently rugged to serve the purpose are at the same time so thin as not to choke the flue in which they are placed. Sheet iron of a thickness from fifteen thousandths to twenty thousandths of an inch is thick enough for the purpose. However, there are no narrow limits within which the thickness of the parts need be confined. Any thickness is suitable which enables the plate to extend horizontally without sagging when supported by its edges, and at the same time leaves sufficient flexibility for two overlapping plates when clamped together in'the manner presently described to bear closely against one another at their overlapping edges even though not exactly in the same plane else where. The thickness of the parts as shown in the drawing has been much exaggerated in proportion to their length and width dimensions for clearness of illustration.

The main plate Ill of the heat conserver is formed with an opening l1 near its rear edge adapted to pass over the stud 18 of the range structure which supports the middle part of the removable bridge I9 of the range top. The angular flanges l2 and 13 are adapted to extend into the narrow spaces between the range top and the opposite side walls, as shown in Fig. 7, and are connected adjustably to the plate l2 by bolts and slots 2! so as to accommodate the device to the exact width of the range. The downturned angular flange I5 is secured adjacent to the front edge of the plate H] by bolts 22 and the forwardly extending angular flange I6 is secured to the flange I5 by bolts 23. These bolts occupy slots which permit adjustment of the flange I5 horizontally and of the flange l6 vertically. The front edge of the plate is turned up to make an upstanding lip or flange 24.

The flanges l5 and iii are adjusted so that the height between the top of the lip 24 and the under side of the flange I5 is equal to the height of the opening between the forward rim 25 of Practically all ranges have such an opening, which is closed by a door 21, hinged at its lower edge, and in which there is usually a damper. Leakage of air may occur around the edges of the loosely fitting door and damper, but the flanges here shown prevent dilution of hot products of combustion by air from this source. Accommodation of the plate to the distance between the opening referred to and the stud i8 is provided by making the slot l1 substantially longer than the width of the stud. Leakage of gases and air through the slot is prevented by a disk 29 having a central hole which fits the stud closely, and having an outside diameter larger than the length of the slot. The plate is secured to the disk by bolts 30 which pass through narrow slots 31 in the plate at opposite sides of the opening I! to permit of the necessary adjustment. By making the central hole ofthe disk 29 fit the upper end of the stud, which is of tapered formation, the disk serves as a suspender for the middle of the rear edge of the plate, preventing this part from sagging. The lip 24 and flanges l2 and I3 establish a space of predetermined depth, in the order of preferably one half inch to an inch, between the plate and the range top; and the nuts on the suspender bolts 38 may be adjusted to bring the rear part of the plate to approximately the same depth.

Holes 32 and 33 are made in the plate I0 directly over the burners 34 and beneath the holes of the range top which are always provided over the fire pot. The edges of these holes are reinforced, preferably by a rod or heavy wire 35 bent into a ring of which the inside diameter is approximately equal to the diameter of the hole, which ring is welded or otherwise suitably secured in a permanent manner to the under side of the plate. Lids 3B are provided for the holes 32 and 33. These are preferably made from disks of the same sheet metal as the plate, larger in diameter than the holes, and having welded to their under side a ring 31 like the ring 35 except that its outside diameter is such that it fits freely within the hole. The lids used most of the time are imperforate; but for some purposes, when a more rapid rise of heat from the burner is desired, a perforated lid 38, shown in Fig. 5, may be substituted for either or both of the imperforate lids. These lids are provided with socket pieces 39 welded or otherwise suitably secured to their upper faces, by which they can be lifted and shifted by the ordinary stove lid lifter. V

a The foregoing detailed description of the reinforcing means for the holes in the heat conserver and of the construction of the lids sets forth what I now consider to be the best construction now known to me. But it is not intended to limit the scope in which I claim protection, and I reserve the right to substitute other constructions for those thus described.

The main part I!) of the conservation device is made short in the direction from the front wall 25 toward the opposite or back wall of the stove in order to facilitate installation in a range already in use. It is in effect extended by the plate II which overlaps, or may be arranged to underlap if desired, at its front edge the rear edge of the main plate and is secured thereto by bolts 40 passing through registering holes 4| and slots 42 in the respective plates. When thus assembled, the two plates are one in effect. The extension plate overlies the top Wall 45 of the baking oven, and may have a length great enough 75' tozfnring .itsrear edgewall the'way'out to the rearmost boundary of the oven. liBothintermediatexedgesoftheextension platexare provided with oifset;horizontal flanges to hook over the :walls of the range in the spaces adjacent to the top always found in kitchen :ranges. One of such flanges is provided by the adjustable angle piece l4 previouslydescribed, and: the opposite flange may likewise be anadjustable piece, but equally well maybe integral with the plate, as shown in Fig. 1.

The heat conserver of this invention is installedin. a range after the lids and bridge bars of the range:top havebeen removed. The flange [6 of themainplate is properly adjusted .asto height, and the plateplaced so that said flange restsontthefront wall while the .lip v24 extends close to, or bears againstthe range top, and the opening I! passes over'the stud I8. The adjustableflange bars [2 and I3 are adjusted to hook over the inner ledges of the'side walls of the range, and the .disk 29 suitably adjusted. The extensionplate is slipped into place .and similarly adjusted, and its overlapping front edge is clamped .to the rear edge ofythe main plate by bolts. The outline of the front plate is made such that its edges approximately fit the interior of the front part of the range. In any case where the fit is not so close as to prevent leakage, asbestos cement may be placed there, and in any other places where cracks appear. The best efficiency with the use of this device is developed by the most complete possible absence of leakage, wherefore it is fitted closely to the bounding walls of the range, and the use of refractory cement is recommended wherever leakage cracks appear. After once being installed no change in the position of the heat conserver is needed throughout its useful life. The bridge bars and lids of the range top may be then replaced, and any of them may be removed and shifted for cooking as desired by the cook.

This device forms a partition extending over the fire space and the adjacent part of the oven, separated from the top of the range by an air space; wherefore it may be designated descriptively as a partition device. It prevents escape into the outer air of gases and soot from the burners. It very greatly reduces heat losses by radiation and convection from the top of the range by reason of the air space above it and beneath the range top. It reflects heat back into the fire pot and guides the products of combustion from the burner over the oven, preventing escape through the discharge flue until after the hot gases have passed around the oven through the spaces left for the hot gases. Thus the oven is more quickly heated, the water in the water front 45 (or equivalent water containing chamber or coil) is heated to a higher temperature and more quickly, and the generated heat is more completely utilized and less of the available heat allowed to escape up the chimney than heretofore. It has been demonstrated in practice that the oven of a range use-d for test has been brought to the highest normal baking heat from a cold condition with the use of one burner only in approximately one hour, as compared with two hours lapse of time with the use of two burners required in the same range before the device was installed. The water in the heating chamber or coil is brought from room temperature to a temperature as high as needed for washing in a few minutes by one burner. Dust and soot are carried :up the: chimney and not released "into the room. The cooking utensils used'on' the topof the stove are not burned or covered with soot.

'What I claim and desire-to secure by Letters Patent is: 1. :Thecombination with a range having atfire pot and an .oven 'beside the fire potand containing passageways for hot gases over and around the. oven, of a heat; conserver consisting of a-substantially'horizontal partition extending over the .fire pot and over the adjacent part of the oven,and separated from the top. ofthe range by an air space.

2. The combination with a range having a fire pot and an oven besidethefire pot and containing passageways for hot gases over and around the oven, of a heat conserver consisting of a substantially horizontal partition extending over the fire pot and over the adjacent part of the oven, and separated from the top ofthe range by an air space, said partition being heat refractory and substantially impervious to leakage of gas.

3. A 'heat conserver for use in cooking ranges consistingof a plate of heat refractory material shaped and adapted to be installed over the The pot and beneath the top of a range.

4. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installed over the fire pot of the range and beneath the top of the range, said plate having an extension adapted to pass into the flue between the top of the range and the oven top in a location sufficiently below the range top to provide an air space and sufficiently high above the oven top to permit an unchoked flow of products of combustion from the fire pot.

5. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installed over the fire pot and beneath the top of a range, said plate having an upturned lip and a downturned flange on its forward edge, the collective height of which is sufficient to span the usual space between the front wall and overlying top of a cooking range.

6. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installed over the fire pot and beneath the top of a range, said plate having an upturned lip at its forward edge, combined with angular flange pieces secured adjustably to its forward edge and to its lateral edges.

'7. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installed over the fire pot and beneath the top of a range, combined with a downturned flange secured to the forward extremity of the plate with provision for adjustment lengthwise of the plate, offset flanges parallel with the plane of the plate extending from its lateral edges, adapted to project between the top and the upper extremities of the opposite side walls of such a range.

8. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installed over the fire pot and beneath the topof a range, an angle piece having a downturned flange secured to the plate parallel and adjacent to the front edge thereof with provision for adjustment transversely of such edge, and an angle piece having a forwardly projecting flange at its lower extremity secured to said downturned flange with provision for up and down adjustment, said last named flange being adapted to rest on the front wall of a range beneath the overlying part of the top of such a range.

9. A heat conserver for use in cooking ranges consisting of a plate of heat refractory material shaped and adapted to be installedover the fire pot and beneath the top of a range, said plate having a hole in thetportion thereof which is adapted to overlie the fire space in a range, combined with a lid having a centering member on its underside adapted to enter the hole and center the lid with its circumference overlapping the rim of the hole.

10. A heat conserver for cooking ranges and the like adapted to be located beneath the top of such a range and over the fire space thereof, comprising a sheet metal plate having an opening adapted to be passed over the bridge supporting stud of such range, the plate having also lateral flanges for engagement with the side walls of a range beneath the top and having at its forward end a downwardly offset flange adapted to be supported on the front wall of a range, said flanges being suitably formed and proportioned to locate the plate beneath and spaced apart from a range top. 7

11. A heat conserver for use in cooking ranges consisting of a partition device of heat refractory material shaped and adapted to be installed over the fire pot and beneath the top of such a range, said device having a downturned flange on its forward edge, the height of which is suflicient to extend from such forward edge to the front Wall of a range across the usual space between such wall and the range top.

12. A heat conserver for use in cooking ranges consisting of a partition device of heat refractory material shaped and adapted to be installed over the fire pot and beneath the top of such a range, combined with a downturned flange secured to its forward extremity with provision for adjustment lengthwise thereof, and offset flanges extending from its lateral edges adapted to enter between the top and the opposite side walls of such range, said offset flanges and the main portion of the device being relatively adjustable for accommodation to the exact width of a given range.

MILLEDGE A. CROSSMAN. 

